HABUR, TURKEY
— Amid the legions of restless drivers waiting at Turkey's only functioning border crossing with Iraq, a sense of fear hangs in the air, as heavy as the smell of crude oil. The oil truckers - about 800 of whom pass through here each day - are deeply worried that an increasingly likely US-led war against Iraq could mean total disruption of their already diminished livelihood.

Before the earlier Gulf War, officials here say, some 2,000 trucks crossed the border each day. The war and subsequent United Nations restrictions on the sale of Iraqi oil put tens of thousands of drivers out of work. Another war, they argue, can only make things worse.

"If they close this border for even two months," says Ilhami Zengin, a middle-aged driver who waits to get back into Turkey, "we won't be able to survive."

Turkey's prime minister, Abdullah Gul, has been delivering similarly dire pleas to avert war with Iraq. Shuttling in recent days to Syria, Egypt, and Jordan - and later this month to Saudi Arabia - Mr. Gul argues that the consequences of a war will be "disastrous" and suggested the countries "consolidate efforts" to stop the march toward a military invasion.

Gul's antiwar tour, aimed in part at improving ties with Arab neighbors, is part of his two-month-old government's evolving response to the Bush administration's game plan for Iraq. The government, led by the Islam-based AKP [Justice and Development Party], promised to bring Turkey out of its economic crisis. That has Turkey's leaders wavering over whether they can accept the costs - both ideological and financial - attached to a war.

In addition to the lost income of small truckers like Mr. Zengin and the higher cost of importing oil for government and big business, Turkey is also wary that war will unleash a new Kurdish refugee crisis. Turkey currently estimates that its financial losses in another Gulf war would be about $28 billion.

Turkey expects the Bush administration to soften the hard edges of assisting the US, which needs Turkey's cooperation to launch an attack on northern Iraq. Washington's game plan for regime change in Iraq includes an attack from the north as well as from the south. Some reports describe a Pentagon plan that would form a "Northern Alliance-style" campaign with the accord and possible assistance of Kurdish groups in northern Iraq. But as a neighbor of Iraq, a NATO member, and a long-standing ally of the US, Turkey and its support are crucial in the operation. Its resistance could deprive the Bush administration of the regional legitimacy it needs to pursue a military campaign.

Senior US treasury officials visiting here before the new year made it clear that the Washington expects to compensate Turkey in exchange for the use of its bases, railroads, and ports. But no aid package is likely to neutralize completely the new government's reluctance to allow the US to use Turkish territory as a conduit for an attack on a fellow Muslim country.

A recent poll by the Pew Research Center found that 83 percent of Turks did not believe the US should be allowed to use Turkey's bases for a war against Iraq. Turkey says it has lost up to $40 billion in trade with Iraq over the past decade. Before the Gulf War, Iraq was Turkey's second-largest trading partner, second only to Germany. And while Washington has not yet announced what the assistance package would be, Turkey has been equally noncommittal. Turkey says it would have to wait for a second UN resolution, which could only come after Hans Blix, the UN weapons inspector, delivers his final report on Iraqi compliance on Jan. 27. Moreover, according to Turkish law, the nation's parliament must approve any stationing of foreign troops on Turkish soil.

But when Turks tally up the income they have already lost - and might lose - the merits of a military intervention in Iraq have become a hard sell for Washington. "If we have a full-fledged war in Iraq, it will cripple Turkish tourism," says Ai Carkoglu, the research director of the Turkish Economic and Social Studies Foundation, a think tank in Istanbul. Turkey's tourism income, he says, totals some $8-$10 billion a year. "Plus, you need to figure how the increase in oil prices will affect us, because Turkey is dependent on foreign oil."

Concerns about access to Iraqi oil figures prominently in Turkey's war jitters. UN sanctions against Iraq after the Gulf War temporarily cut Turkey off from one of its main suppliers. But for years, Ankara looked the other way at illegal trade through the border.

Turkish officials say last year they came under renewed US pressure to enforce the sanctions, and the importation of diesel - but not crude oil - was stopped. Outside analysts and Western diplomats, however, say Turkey's decision to cut off the diesel trade was motivated by political interests. Turkey realized that the Kurdish Democratic Party [KDP], one of the main parties in northern Iraq, was getting wealthy from the diesel proceeds and helping to pave the way to de facto Kurdish autonomy. The possibility of the KDP or other Kurdish parties coming to power in a post-war Iraq - as part of a democratic Iraqi federation - is seen as a potential threat.

Turkey worries that any further political empowerment of Kurds in Northern Iraq could encourage Turkey's Kurdish population to relaunch a guerrilla war, just a few years after Kurds here relinquished armed conflict upon the capture of PKK [Kurdistan Workers Party] leader Abdullah Ocalan in 1999.

Turks are also concerned that Iraqi Kurds could use the collapse of the Iraqi government to make a grab for the oil fields of Kirkuk and Mosul Provinces. Turkey warned US officials that if that happens, the Turkish Army will intervene. As evidence of those intentions, Turkey has recently doubled its military strength in northern Iraq to 12,000 soldiers, the Associated Press reports, quoting an unnamed senior intelligence source.

While Turkey's official position is that war should be averted, it has not ruled out the possibility of benefits to regime change in Iraq. Yasar Yakis, Turkey's foreign minister, said this week that Turkey might have a legitimate claim to the northern Iraqi oil fields.

Mr. Yakis told the prominent Hurriyet newspaper that he is examining early 20th-century treaties to see if Turkey has a right to claim the vast oil fields of Kirkuk and Mosul, which the Turks ruled under the Ottoman Empire. "If we do have such rights, we have to explain this to the international community and our partners in order to secure those rights," Yakis said.

Part of Turkey's claims and concern for the region lies with the native Turkomen population of northern Iraq, whom Turkish officials view as oppressed by the Kurdish parties there. Turkey has told US officials that it would feel obligated to defend endangered Turkomen - ethnic Turks - and that they should have a large say in any postwar government in northern Iraq. But while Turkish estimates put the number of Turkomen at anywhere between 3 and 5 million, US officials believe the number does not exceed 700,000.

For businesses in this poorest and least-developed corner of Turkey, it is difficult to imagine how the economy could handle another war. At least 70 percent of the local economy revolves around agricultural production, and Iraq is one of the hungriest clients for what is sold here. Baghdad has been allowed to buy food and other goods from Turkey under the oil-for-food program.

According to the Southeastern Anatolian Industrialists and Businessmen's Association in Diyarbakir, the capital city of the south, some 52,000 trucks have been put out of work by the restrictions on Iraqi oil sales. Depots of them fill fields near the border like failed, burned-out crops.

At Habur, lodged between snow-capped Turkish and Iraqi mountains, the atmosphere is grim. The deputy governor of the crossing says that between 8,000 to 9,000 tons of crude oil come through here each day: far below capacity and slipping. Some drivers are no longer going to Iraq, fearing they could get caught in the crossfire.

That uncertainty hangs heavily over Habur. Halil Aral is a driver who feeds a family of eight on earnings of between $300 and $600 a month, depending on how many trips he can manage to make. "If this border will close," he says, "we will meet starvation."